import java.util.Arrays;
import java.util.Scanner;
public class jobs {
static final int mxn = 1000005;
static Pair[] a = new Pair[mxn];
static class Pair {
int fr, sc;
Pair(int fr, int sc) {
this.fr = fr;
this.sc = sc;
}
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int n = scanner.nextInt();
int d = scanner.nextInt();
int m = scanner.nextInt();
for (int i = 1; i <= m; i++) {
a[i] = new Pair(scanner.nextInt(), i);
}
a[m + 1] = new Pair(1000000000, 0);
Arrays.sort(a, 1, m + 1, (p1, p2) -> Integer.compare(p1.fr, p2.fr));
int l = 0, r = m;
while (r - l > 1) {
int mid = (l + r) / 2;
int p = 1;
for (int i = 1; i <= n; i++) {
if (a[p].fr + d < i) {
break;
}
int cnt = 0;
while (cnt < mid && a[p].fr <= i) {
cnt++;
p++;
}
}
if (p > m) {
r = mid;
} else {
l = mid;
}
}
System.out.println(r);
int p = 1;
for (int i = 1; i <= n; i++) {
int cnt = 0;
while (cnt < r && a[p].fr <= i) {
cnt++;
System.out.print(a[p].sc + " ");
p++;
}
System.out.println(0);
}
scanner.close();
}
}
